Genetics 1 Principles Of Inheritance Flashcards
Genetics is the branch of biology which deals with
Inheritance of characters and variations
Define inheritance
Transfer of characters from one generation to another
Define variation
Degree of dissimilarities between parents and offsprings or members of same species
Father of genetics
Gregor J Mendel
Father of modern genetics
W Bateson
Who gave the term genetics
W Bateson
Father of experimental genetics
T H Morgan
TH Morgan did an experiment on ___
Drosophila (fruit fly)
TH Morgan gave the concepts of (6)
Crossing over Recombination Linkange Cross cross inheritance Sex linkange Linkage map of drosophila
Father of human genetics
A Garrod
___+___= genetics
Inheritance
Variations
Father of biochemical genetics
A Garrod
Father of human and biochemical genetics
A Garrod
A Garrod discovered _____ known as ____ or ____
First human metabolic genetic disaster
Alkaptonuria (black urine disease)
A Garrod gave the concept that
1 gene= I metabolic block
Variations that were naturally present in wild populations of plants and animals were selectivly bread (past of breed) and organisms which desirable characters produced. An example of this ?
Sahiwal cow in Punjab
Types of variations
Somatic variation
Germinal variation
What are somatic variations
Non inheritable variations like broken tail of mice
_____ variations are inheritable
Germinal variations
Germinal variation can be divided intine
Continuous and discontinuous variation
Continuous variation occurs due to ____
Crossing over
Discontinuous variation occurs due to
Mutations
Just read this :)
Discontinuous variation occurs randomly
Discontinuous variation can be divided into
Substantive
Meristic
Substantive variations affect ________________________
Shape
Size
Color
Examples of substantive variations
Short legged Ancon sheep
Hornless or polled cattle
Hairless cats
What are meristic variations
They affect number of parts
Example of meristic variations
Polydactyly (6 or more digits in human)
Mendel proposed that something was being stably passed down, unchanged from parent to offspring through the gametes in successive generations these were called
Factors
Now, factors are called ___
Genes
The term gene was given by
Johannsen
Gene is defined as
Functional unit of inheritance
Chemically, what is a gene
Segment of DNA that has a particular function (synthesis of polypeptides)
1 gene makes _____ which makes 1 ___ which does one metabolic activity which produces 1 ___
Protein
Enzyme
Characteristic
Genes are located on
Chromosomes
Alkaptonuria or black urine disease ,_____ enzyme is deficient
Homolgentisic acid oxidase
Germinal variations are aka
Blastogenic variations
genes which code fir a pair of contrasting traits are known as ____
allels
___ are slightly gifferent forms of the same gene
alleles
the term allele was used by__
bateson
allele is abbreviated form of term ________
allelomorphs
external appearence or morphology of plant part is known as
phenotype
phenotype is controlled by (2)
geneotype and environmental conditions
what is genotype
genetic makeup or genetic compositionfor any phenotype is known as genotype
if both alleles are same in an individual it is known as _____. eg.
homozygous
TT,tt
if both copies of gene are of different type in an individual it is known as
heterozyygous condition
what is hemizygous condition
in a diploid organism, if only 1 factor is responsible for characters, it is known as hemizygous condition
eg of hemizygous condition
human male is hemizygous for sex linked genes
what are phenocopies?
if different genotypes are placed in different environmental conditions and consequently they produce same phenotype, these genotypes are phenocopy of eachother
pre mendelian gentics was also known as
blending inheritance
what is blending inheritance
before mendel it was assumed that genetic material is of liquid or fluid nature
medels full name
gregor johann mendel
mendel was born in the year ___ at ___ in ___
1822
heizendorf
austria
mendel worked as a __ in brum city, austria
monk
mendel dies in the year ___ due to ____ disease or kindney failure
1884
bright disease
life span of menderl
62 years
mendel did experiments on pisum sativum for __ years from __ to ___
7 years
1856-1863
pisum sativum is aka
garden pea
a paper of mendel by the name ___ was published in __ journal, by the natural history society of ___
experiment in plant hybridisation
nature for schlender varien
Brunn
after ___ years of mendels death in the year ___, 3 of his students published experiments and results of mendel as mendelism
16
1900
name the 3 students of mendel and their country
carl correns (germany)
hugo de vries (holland)
tschemark (austria)
what did carl correns, hugo de vries, tschesmark do?
they published experiments and results of mendel as mendelism after 16 yrs (1900) of mendels death
what are the 3 reasons for failure of mendel
due to lack of communication
fame of darwins ideas
mendels method of mathematical and statistical analyisis was not accepted by scientists of that time
5 reasons of success of mendel
he studied inheritance of only 1 or 2 characters at a time
selection of garden pea for studying
quantitatively analyzed the inheritance of qualitative characters
mendel maintained statistical results of all his experiments
studied 7 pairs of contrasting characters on 4 pair of chromosomes (1,4,5,7)
carl correns did experiments on
maize
hugo de vris did experiment on
evening primrose
aka
oenothera lemarciana
tschesmark did experiments on
different flowering plants
stem height was on ___ chromosome and dominatnt feature? and recessive?
4th chromosome
d-tall
r-dwarf
flower position was on ___ chromosome and dominatnt feature? and recessive?
4th chromosome
d-axial
r-terminal
pod shape was on ___ chromosome and dominatnt feature? and recessive?
4 th chromosome
d-inflated
r-constricted
pod color was on ___ chromosome and dominatnt feature? and recessive?
5th chromosome
d-green
r-yellow
seed shape was on ___ chromosome and dominatnt feature? and recessive?
7th chromosome
d-rounded
r-wrinkled
seed color was on ___ chromosome and dominatnt feature? and recessive?
1st chromosome
d-yellow
r-green
flower color was on ___ chromosome and dominatnt feature? and recessive?
1 chromosome
d-violet/red
r-white
out of the contrasting characters that mendel chose, ___ characters are present for seed
2 (seed shape and seed color)
out of the contrasting characters that mendel chose, ___ characters are present for flower
2 (flower position and flower color)
out of the contrasting characters that mendel chose, ___ characters are present for stem
1 (stem height)
out of the contrasting characters that mendel chose, ___ characters are present for pod
(pod shape;pod color;flower position(as flower position determines pod position)
mendel used __ and ___ technique for cross pollination of pisum sativum
emasculation
bagging
fertilisation between male and female results in formation of _____
first filial generation (F1)
if plants of F1 generation are ____, F2 generation is achieved
self pollinated
what is the monohybrid ratio
3:1 (dominant:recessive)
what is the genotypic ration of monohybrid cross
1:2:1
what is monohybrid cross
when we consider inheritance of only 1 character in a cross
___&___ law were based on monohybrid cross
law of dominance and law of segregation
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when 2 diferent unit factors are present in single individual of F1 generatoin , only 1 unit factor can express itself called dominant unit factor and the other one which fails to express itself is called recessive unit factor
law od dominence is based on __generation
F1 generatiuon
___ and ___ are exceptions of law of ddominence
incomplete dominance
co-dominance
law of segregation is based on ___ generation
F2
just readf this ○( ＾皿＾)っ Hehehe…
law of segregation: during gamete formation, unit factors of a pair segregate randomly and reach to different gametes.each gamete revieves only 1 factor, so gametes are pure for a particular trait
what is the first law of inheritance
law of dominance
law of segregation is aka
law of purity of gametes
what is the biological basis of law of segregation
separation of homologous chromosomes during anaphase 1 of meiosis
formula for number of gametres
`2^n n
n=no of heterozygosity
number of offspring/zygote
no of gametes^2
number of types of phenotype
2^n
no of types of genotype
3^n
flowers of pisum sativum naturally show which type of pollination
pisum sativum naturally show self pollination
true or false: a true breeding line shows stable trait inheritance
true
true breeding line=homozygous
stable trait inheritance: no variation
pisum sativum produce a ___ no of offspring and completes in life cycle in ___ season(s)
large no of offspring 1 season (annual plant)`
how many true breeding plant variations were taken by mendel
14
when we study 2 pairs of contrasting characteristics in an inheritance it is called ___
dihybrid cross
eg of dihybrid cross
round and yellow seed crossed with wrinkled and green seeded pure plant
in dihybrid cross, on selfing between F1 generation, phenotypes are obtained in _____ ratio
9:3:3:1
on the basis of __________, mendel proposed a 3rd law of inheritance aka
dihybrid cross
law of independent assortment
biological basis of 3rd law
the non homologous chromosome show random distribution at metaphase plate during metaphase 1
________ is an exception of independent assortment
linkage
probability of n number of sons/daughters to a couple
(1/2)^n
what is back cross
cross between F1 progeny and parents (either dominant or recessive)
back cross is divided into (2)
out cross and test cross
what crossing occurs in out cross
F1*dominant parent
what crossing occurs in test cross
F1 * recessive parents
monohybrid test cross ratio
1:1
dihybrid test cross ratio
1:1:1:1
to know the genotype of dominant character ____ is used
test cross
if linkage is present, ratio of dihybrid test cross is changed from 1:1:1:1 to _______ (coupling)
7:1:1:7
if linkage is present, ratio of dihybrid test cross is changed from 1:1:1:1 to _______ (repulsion)
1:7:7:1
____ is when dominent tries to remain with dominant and reccessive with recessive
coupling
when dominant gene tries to retain with recessive and recessive with dominant it is called
repulsion
types of gene interaction
allelic and non allelic
what is allelic gene interaction
interaction between alleles of a single gene
what is non allelic gene interaction
interaction between alleles of more than 1 gene
give 5 examples of allelic gene interaction
incomplete dominancy co dominancy multiple allesim pleotropy lethal gene
examples (4) of non allelic
epistalsis
complementary gene
duplicate gene
polygenic inheritance
what is incomplete dominance
if F1 hybrid does not resemble to any of the parents and shows intermediate phenotype of parent
incomplete dominancy is the result of ___
blending inheritance
incomplete dominancy was discovered by ____ in ___
correns mirabilis jalapa (4 o clock plant)
4 examples of incomplete dominance
flower color of mirabilis
flower color of snapdragon (dog flower/antirrhinum)
starch grain size of pea
feather color andalusian fowls(chicken)
flower color of snapdragon F1 ratio
pink (Rr)
phenotypic ratio of flower color of snapdragon
1:2:1 (red:pink:white)
genotypic ratio of flower color of snapdragon
1:2:1 (RR:Rr:rr)
what is the phenotype of size of starch grain (of pea) F1 generation
medium sized
phenotypic ratio of F2 of starch grain of pea size
large:medium:small
genotypic ratio of inheritance of starch grain of pea
1:2:1 (BB:Bb:bb)
if the phenotype of the F1 hybrid resembles to both the parents (both express together) it is called
co dominancy
give 3 examples of co dominancy
skin color of cattle
AB blood group
carrier of sickle cell anemia
f1 generation of co dominancy of skin color of cattles produces ____ cattle
roans ( consisting of 2 differrent colors)
what is multiple allelism
if character is controlled by more than 2 alleles of a gene
in multiple allelism, multiple alleles are on same ____ of homologous chromosome
locus
____ can only be found when POPULATION studies are made
multiple alleles
ABO blood group of human has ___ alleles
3
eye color of drosophila has ___ alleless
12
coat color of rabbits has __ alleles
4 alleles
ABO blood group is controlled by gene: ___
I (capital i)
gene I is present on chromosome no ___
9
the 3 alleles of ABO blood grouping
Ia
Ib
Io/i
what is the function of Ia
forms sugar on plasma membrane of RBCs called antigen A
what is the function of Ib allele
forms sugar on plasma membrane of RBCs called antigen B
alleles IA and IB are dominant oven allele ____ but IA and IB are ____
IO
co dominant
for blood group, ___ phenotypes and ___ geneotypes are present
4 phenotypes
6 geneotypes
in diploid organisms, ___ alleles of a gene are present
2 alleles (thus all 3 allels of gene I can be analysed in human POPULATION)
if IAIB is the genotype, which antigen is present on RBCs
A and B
if IOIO genotype is present, which antigen on RBCs
no antigen
type of phenotype in multiple allelism
n+1 (n=no of alleles)
eg. blood grp. 3+1=4
no of genotype for multiple allelism formula
(n)(n+1)/2
which blood group is universal donor
o
which blood group is universal acceptor
AB
what is lethal gene
gene responsible for death of individual is known as lethal gene
lethal gene shows lethality when it comes in ____ condition
dominant
true or false: lethal gene may be dominant or recessive
true
in yellow coat of mice, ____ condition is lethal
homozygous dominant (YY)
in yellow coat color in mice, Y represent ___, and y represent __
yellow coat color (dominant)
brown coat color
ratio of phenotype and genotype of yellow coat of mice F1 generation
2:1 (as YY dies before being born )
what is pleiotropic gene
more than 1 gene controls many characters
____ gene shows multiple phenotypic effect
pleiotropic gene
multiple phenotypic effect occurs when product of gene effects more than 1 metabolic pathway and thus effect different phenotype
:)
in drosophila, gene of wing size also affects: (3)
fertility
shape of spermatheca
eye color
sickle cell anemia is a _____ disease
autonomous (not controlled by sex chromosomes, controlled by autosomes)
sickle cell anemia is a ___ trait
recessive
sickle cell anemia is caused by substitution of ___ with ___ at 6th position of ____ of Hb molecule
glutamic acid
valine
beta globin chain
sickle cell anemia is caused by substitution of glutamic acid with valine at___ position of beta globin chain of Hb molecule, due to substitution of codon : ____ by ____ on ___
6th position
GAG
GUG
mRNA
in sickle cell anaemia, transversion takes place
:=)
disease is transmitted from parent to offspring when ___
both the parents are carrier of gene (heerozygous)
carrier of sickle cell anaemia is a result of _____. they are semi lethal
co dominance
in human genes of sickle cell anaemia, HbS is lethal in ___ condition
homozygous
the process of formation of mRNA from DNA is called
transcription
the process of formation of protein from mRNA is called
translation
non allelic gene interaction?
interaction between alleles of 2 different genes ie interaction between alleles present on diffeerent loci
complimaentary gene is an example of ____
non allelic gene interaction
complimentary gene was discovered by ___&___
bateson and punnett
the experiment by bateson and punnett wad performed on
Lathyrus odoratus
bateson and punnett used used _____ (number,color) flowers plant for the cross of lathyrus odoratus
2 white colored
